ICGA Journal - Volume 36, issue 1

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ISSN 1389-6911 (P)

ISSN
2468-2438 (E)

Impact Factor 2019: 0.500

The ICGA Journal provides an international forum for computer games researchers presenting new results on ongoing work. The editors invite contributors to submit papers on all aspects of research related to computers and games. Relevant topics include, but are not limited to:

(1) the current state of game-playing programs for classic and modern board and card games(2) the current state of virtual, casual and video games(3) new theoretical developments in game-related research, and (4) general scientific contributions produced by the study of games.

Also welcome is research on topics such as:
(5) social aspects of computer games
(6) cognitive research of how humans play games
(7) capture and analysis of game data, and
(8) issues related to networked games are invited to submit their contributions.

Abstract: In this article we investigate how three multi-player search policies, namely maxn , paranoid, and Best-Reply Search, can be embedded in the MCTS framework. The performance of these search policies is tested in four different deterministic multi-player games with perfect information by running self-play experiments. We show that MCTS with the maxn search policy overall performs best. Furthermore, we introduce a multi-player variant of the MCTS-Solver. We propose three update rules for solving nodes in a multi-player MCTS tree. The experimental results show that the multi-player variant of the MCTS-Solver is a genuine improvement for MCTS in multi-player…games.
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Abstract: Depth-first proof-number (df-pn) search is an effective sequential AND/OR tree search algorithm using the notion of proof and disproof numbers. Although df-pn has been parallelized in shared-memory environments thus far, parallelizing df-pn in distributed-memory environments still remains a challenge. This paper presents simple yet empirically effective parallel df-pn methods for distributed computing environments. Our methods are based on parallel dovetailing that has been successfully applied to a number of algorithms and they incur almost no communication overhead by independently performing df-pn search that exploits a different part of the search space in each processing node. More specifically, we present two…methods of parallelizing an enhanced df-pn variant called df-pn+ : the first is based on leveraging non-deterministic behaviors of a shared-memory parallel df-pn search algorithm (SPDDFPN+ ), and the second is based on randomly initializing proof and disproof numbers (RPDDFPN+ ). Experimental results using state-of-the-art solvers indicated that RPDDFPN+ achieves reasonable speedups in both tsume-shogi (checkmate problems in Japanese chess) and tsume-Go (life-and-death problems in Go), which have completely different characteristics. Moreover, parallel dovetailing occasionally yields superlinear speedups with a reasonably small number of base solvers and can even solve additional instances that the original solver is unable to solve. Our results also revealed that SPDDFPN+ improves the efficiency of a high-performance tsume-shogi solver.
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Abstract: Chomp is a poset (partially-ordered set) game invented by Gale (1974). Its starting position is a rectangular grid of squares, one corner of which is the special poison square ; without loss of generality, we assume it is always in the lower-left corner. Players take turns choosing a square and removing it along with all squares to its right or above it or both. The player who removes the poison square loses the game. This note introduces a solver software for GNU tools on a POSIX system that can solve the game for reasonable starting positions. The software took…about 8 days to solve all positions up to the 16x16 square. This software is freely available on SourceForge under the project name Chocoholic. This note describes the software, some things noted about the solution, and some possible future developments.
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